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How to tell whether a person is lying or telling you the truth?

  1. Jun 30, 2003 #1


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    Are their any signs eg., eye movement, pupilary response, etc... And are any of you good at spotting the nots?
  2. jcsd
  3. Jun 30, 2003 #2
    There are many theories about this, but there's no real way to tell...
    I guess if it looks like they're making something up then maybe, but they might have already made up there response already...
    Hard to say.
    I study psychology and there's nothing from that field I've heard of.
  4. Jun 30, 2003 #3

    Yes - there are some ways that are helpful sometimes.

    But I am NOT going to list them, because they will most likely get BLOWN out of porportion and rearanged to say thing they are NOT.

    So, if you want to know if someone is lying - get a lye detection machine.

    You can buy them at sharperimage
  5. Jun 30, 2003 #4
    there are the obvious ones like voice intonation and eye contact, sweating (if they're really nervous), along with much more subtle ones like pupil dialation and nostril flares. if you know what to look for, it's pretty easy to tell.

    and in answer to your second question, i am fairly good at picking up these responces, if i say so myself. it helps a lot if you're wearing sunglasses that hide your eyes so that they can't see you looking across their face.
  6. Jun 30, 2003 #5
    Re: Re: How to tell whether a person is lying or telling you the truth?

    lie detection machines are not the best way. sure, they almost always tell you when someone is lying, the problem is they tell you that they're lying when they're not. if your even the slight bit nervous, the machine will pick it up and misinterpret it.
  7. Jun 30, 2003 #6


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    Re: Re: How to tell whether a person is lying or telling you the truth?

    why would i do that? I can build one! Its basically a resistance and temperature machine hooked up to our skin. I believe our skin is about 50ohms which like wire changes with different temperatures that corresponds to our senses. Interesting huh? A cheap one could be built for $5.00 or less. But you get what you pay for and thier are more technical diagrams for design of really nice ones. Seriously now, who has time or how could you get someone hooked up to one if they already know their lying? Go ahead and be open and share some secrets plz. I wont pick fun or laugh, promise!
  8. Jul 1, 2003 #7
    It is not always acceptable to hook everyone up to a lie detector before starting a conversation with them.

    Obvious signs are looking away, touching the face, twitching, and looking down and to the left.
  9. Jul 1, 2003 #8
    IMO if he/she really wants to lie to you I can't tell. All other signs can be interpreted if you really know how the other person reacts and if he/she is not used to lie to you.
    C'mon people you've never lied to your wife about a late meeting at work when you were at the bar watchig the game (whatever game you prefer...)? Did she catch you?
    I have to say that I haven't done this very often and I'm not proud of it.... so don't do as I do
  10. Jul 1, 2003 #9


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    Science Advisor

    Greetings !

    The only rather certain ones I know of are eye movements.
    When a person's eyes look down and to the left when he's
    about to say/answer something he's accessing his brain's
    memory and processing parts. When the eyes go up and to the
    right his accessing the parts responsible for imagination.
    (At least that's what the experts say and it seemed to work
    for me.) I suppose there may be other signs that deal with
    the same basis (accessing brain functions). I also suppose
    that a person could intentionally avoid making such signs
    after some practice, if he knows about it of course. At least
    these signs are easier to notice and a person has to know
    about them to try and avoid them (unlike the more popular
    and coomonly faked sweating, shaking, not looking in the eyes
    and so on).

    Now here's a Q for you - how do you know that someone on the
    Internet lies to you ?

    Live long and prosper.
  11. Jul 1, 2003 #10
    Re: Re: Re: How to tell whether a person is lying or telling you the truth?

    1. Stop spreading misinformation. This statement is absolutely 100% false.

    2.I have worked with lie detection machines for over a decade - and built many. Never ever EVER has a properly operating lie detection apparatus EVER produced an incorrect result.
  12. Jul 1, 2003 #11
    Re: Re: Re: Re: How to tell whether a person is lying or telling you the truth?

    Is that why they use them in Court?
  13. Jul 1, 2003 #12
    Re: Re: Re: Re: Re: How to tell whether a person is lying or telling you the truth?

    The court using them is another sign that indeed they are beyond a reasonable doubt, yes.
  14. Jul 1, 2003 #13
    Re: Re: Re: Re: How to tell whether a person is lying or telling you the truth?

    almost every phyciatrist (or do i mean phyciologist?) will tell you that lie detector machines are not the best way to tell if a person is lying.
  15. Jul 1, 2003 #14
    Re: Re: Re: Re: Re: How to tell whether a person is lying or telling you the truth?

    Claims require evidence. Show us all a survey that provides this (mis)information.

    BTW - you won't find one.
  16. Jul 1, 2003 #15
  17. Jul 1, 2003 #16
    Ok I feel I must share with you the only medically proven way to tell if someone's lying. However this is quite complexed, so pay close attention..

    1. Look someone straight in the eye
    2. Scream at the top of your voice "you're a LIAR!
    3. If they confess, they are lying. If not, claim you actually said "you're on FIRE" and act bewildered that they're not.

    Write down these steps carefully.

    If that fails, just hypnotize them :wink:
  18. Jul 2, 2003 #17
    try torcher
  19. Jul 2, 2003 #18


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    Dx LHFAQ!
  20. Jul 3, 2003 #19
    Re: Re: Re: How to tell whether a person is lying or telling you the truth?

    A good polygraph operator will intersperse ordinary questions in with the pertinent questions. This way he gets a baseline for respiration rate, GSR, pulse, etcetra. Currently, polygraphs are considered between 98 and 65% accurate at detecting lies.
  21. Jul 8, 2003 #20
    a skilled liar can pass a polygraph, and someone who is telling the truth can fail it miserably if they're very nervous...ergo, the polygraph is codswallop and that's why it's not admissible in most courts of law. however, there is a whole science devoted to the study of lying. you might be able to research it online if you want to find out about it.
  22. Jul 8, 2003 #21
    Research would also tell you that the polygraph was invented by the same man who came up sith SOMEONE'S favorite magic-lasso wielding superhero! Yep, Wonder Woman's lasso that makes you tell the truth was the idea of the inventor of the lie detector.
  23. Jul 8, 2003 #22


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    I heard alot of special forces guys are trained to do just that. They're training involves being able to pass a polygraph test if captured to evade questioning and giving up top secret info.

    Kool! Not cool as a POW but cool training, i wish i could try doing that, anyone else?
    Dx :wink:
  24. Jul 8, 2003 #23
    A skilled liar is only a little better at passing a polygraph. A pathological liar will pass it every time. A fear of possible detection is important.

    Assuming you have a highly skilled operator, just being nervous won't make you fail, but it may make the test invalid - making a baseline unobtainable.

    Training with biofeedback can enable you to beat a polygraph, and keeping a small tack thru your shoe, into the toe area, allows you to covertly jab yourself anytime you get a question (baseline or experimental), spiking your readings, thus keeping the operator from determining a baseline.
  25. Jul 10, 2003 #24
    Some biological characteristics of lying are:

    1) increase in body temperature
    2) increase in sweat secretion
    3) increase in pulse
    4) pupil dilation

    Some behavioral effects of lying are:

    1) looking down and to the left
    2) covering part of the face with the hand
    3) crossing the arms
    4) general nervousness and broken speech

    ***HOWEVER*** Not everyone reacts the same way to the same situation. So there is no DEFINITE way to tell whether or not someone is lying. Some people can train themselves to be a good liar by monitoring their behavior or by using biofeedback. That is why the results of a lie detector test cannot be used as evidence in a court of law.
  26. Jul 14, 2003 #25


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    I have a relative that seems to lie constantly for no reason. None of us can figure out why he lies. He comes with the stupidest stories. I am not sure he even knows he is lying. I have often wondered how he would do on a polygraph test.
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